An end-user can close a document by clicking a close ('x') button. The Close method allows you to close a document in code.
When a document is closed, it and its contents are destroyed. To temporarily hide a document, use the BaseView.RemoveDocument or RemoveDocument method.
To prevent a document from being closed, handle the BaseView.DocumentClosing event or use the IBaseDocumentDefaultProperties.AllowClose/IBaseDocumentProperties.AllowClose properties.